Tests to determine the behavior of two microturbines running in parallel were performed under CERTS (Consortium for Electricity Reliability Technology Solutions) funding in 2001. A report describing the results of these tests "Behavior of Capstone and Honeywell Microturbine Generators during Load Changes" was published by Lawrence Berkeley National Laboratory (LBNL-49095) in July 2001 for CERTS. In these tests, two microturbines were run in parallel with very little impedance between them. The test was first performed for two Capstone 30 kW microturbines in parallel and then one Capstone 30 kW microturbine and one Honeywell 75 kW microturbine running in parallel. No unstable operations were observed as part of any of these tests.

This report describes a second set of tests to look at parallel operation of two microturbines when there was sufficient impedance between them to give a 4\% - 5\% voltage drop at full load operation. This is to simulate the behavior of microturbines being operated by neighboring customers at the same time. Two tests were conducted for this report. The first test operated two microturbine/ load bank pairs using manual control of the microturbine and load bank setpoints. The second test used the Capstone Load Following mode of operation to control the generation level of one microturbine.